Cheap (or free) inverters

Jim Blackwood · December 18, 2018, 12:53:29 PM

So here are the inverters that came with the bus. I don't really know how good they are or aren't. Says they're "The Best" of course (Designed for Military Applications) but that could mean anything.

Anybody ever heard of this brand?

Jim

richard5933 · December 18, 2018, 01:13:54 PM

Seems like about a grand worth of inverters. Here's the page from donrowe.com about them:

https://www.donrowe.com/power-bright-ml900-24-inverter-p/ml900-24.htm

You can download the manual and spec sheet from their site.

Jeremy · December 18, 2018, 03:32:39 PM

"Cheap" probably seems correct judging by their appearance - but why are there so many? What was your bus used for before you got it?

Jeremy

richard5933 · December 18, 2018, 03:51:07 PM

These appear to be at least 'okay' inverters, but the problem is that they are only 900-watt units. I did a bit of research, and so far I'm seeing that it may not be possible for you to run these in parallel to get higher output since they are modified sine wave (MSW) and not pure sine wave (PSW).

If you plan to run a few smaller appliances, that these might work for you. Assuming that the MSW works for what you plan to plug in.

Not sure what the resale is on something like this - they can be purchased new for about $80/ea.

Geoff · December 18, 2018, 04:18:47 PM

It is obvious these inverters were placed in the bus for laptop and phone charging.

buswarrior · December 18, 2018, 05:10:59 PM

Interesting strategy, single failure doesn't take out the whole coach.

Today's run of the mill coach has a single big inverter mounted to the roof of a bay, serving all 56 seats.

Drivers quickly learn how to reset it, there's no limit to what condition the customer's electric goodies might be in...

Then a good old fashioned vigilante hunt starts for the offender, when it trips again...

Sgt Shultz in the driver's seat... I see nothing...

Happy coaching!
Buswarrior

Dave5Cs · December 18, 2018, 08:50:39 PM

you can tell a decent inverter from a cheap one that will fail soon by the weight. cheap one have very small (Read Overheat) transformers and good one have very heavy with lots of winding's type transformers and a good fan inside.

Jeremy · December 19, 2018, 02:56:13 AM

I think I'd still rather have a single commercial-spec inverter with a continuous duty rating serving all the seats than multiple throwaway budget jobs. It would be simplicity itself to design circuitry which disconnected individual outputs if too much current was being drawn by a particular passenger

Jeremy

Jim Blackwood · December 19, 2018, 07:27:34 AM

I'd rather have a single large inverter for the conversion, but I think these will do fine. They have some heft and there is a fan. Specs said they'd handle 1800W of surge current and they are claimed to be good on starting surges. Probably my heaviest demand will be with a power hand tool of some sort like an angle grinder, or the wife's blow drier. Maybe a vacuum cleaner. Hey, if I blow one up I'll know it can't handle the load. Not like I don't have any redundancy.

Since it would take a very special inverter to do load sharing I'm not even going to attempt that, although now that I consider it, I'm sure it'd be possible to physically hack them to tie the drivers together and run them off one controller. Probably more than I want to mess with. If I was younger... but no. Not worth the time and effort. (although I could open one up and look...) I have the power distribution center for them and some very nice wiring, each one on a separate breaker. The biggest issue will be locating and mounting them to make the AC convenient.

I have the indirect florescent lighting to consider, one inverter would run all that. Or I may change over to LEDs. No hurry. The wiring can be run inside the cabinets and mounting the inverters will be one of the last things I expect. In the meantime they aren't eating anything.

Jim

I will need a battery charger, but that can come later.

Fred Mc · December 19, 2018, 10:35:36 AM

I would do all LED over flourescent. Wiring is smaller, LED's probably cheaper even now and of course uses less power. For me a no-brainer.

Geoff · December 19, 2018, 02:12:34 PM

I've tried using LED lights and find them irritatingly bright indoors.

Jim Blackwood · December 19, 2018, 02:21:23 PM

Look for the "warm white" version.

richard5933 · December 19, 2018, 02:53:37 PM

Custom Coach installed dimmable florescent lights. We added full-function 12v LED (with separate white/RGB rows). I much prefer the quality of the light coming from the florescent lights, but the LED are sure handy when we're running on battery.